The key thing is that it fits you and the horse, and doesn't put you into some kind of weird position. You want to be able to sit more upright than you would usually do in a jumping saddle, but the endurance saddle ought to work.
I don't know whether this is anything that would work for you, but I wanted to throw it out there just in case...I board my horse, and my barn has got a couple of non-horse-owing high-quality lesson students. They're people who are working for lessons, in some cases, in other cases, they're people who have had horses before but don't now because their pockets or schedules won't allow for it. I've met several of them, and checked for myself that they're good riders, and good people, and my horse likes them...so when I need to go away for a week or so, I let my trainer use my horse to give those people lessons on. It's a very short list, and she doesn't put anyone up on my horse that I haven't already approved. But it's a really good setup, because my horse gets exercised, my trainer gets the use of a high-end horse for her advanced students, the students get to ride something other than a schoolmaster, and I get some free training for him. I know it's not for everyone, and I would have been pretty reluctant to entertain the thought of Other People riding my boy, but it's been working out incredibly well.